Cold metal working oil



[Vuk/ FIDRnnQ Patented May 13, 1941 COLD METAL WORKING OIL George W. Flint, Chicago, Ill., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application March 17, 1938, Serial No. 196,365. Renewed May 13, 1940 11 Claims.

This invention relates to improved cold metal working oils and more particularly to non-ferrous metal and/or alloy cold rolling and processing oils.

In the cold rolling of non-ferrous metals and/or alloys, particularly nonferrous metals such as copper, copper alloys and brass. the stock is processed from slabs of about one inch in thickness and of various widths and lengths and'the slabs rolled to strip stock having a thickness of from about A; inch to about inch from which the finished sheets are finally rolled to dimension. The thin finished sheets may have a thickness of the order of about 0.0001 of an inch. Briefly described, the cold rolling mills generally comprise two solid highly polished steel rolls about two feet in diameter mounted one above the other and provided with means for controlling the clearance between the same. The rolls arerevolved at substantially the same rate to avoid rubbing action during the rolling. During the rolling operation the rolls are kept cool by a stream of water passing down over the same. As the metal stock is introduced into the rolls a lubricant is applied to both sides of the stock at regular intervals by means of a swab or automatic lubricator and is then distributed evenly over the stock by means of a felt distributor which is located just ahead of the rolls. As the rolled stock leaves the rolls it is coiled upon a platform and transferred to annealing ovens wherein it is annealed before being subjected to further rolling operations. After the stock is annealed it is treated in a pickling bath, washed and then subjected to another rolling step for further reduction in size. This procedure is repeated until the stock has been reduced to the desired dimensions.

Heretofore, the stock has been lubricated with material such as straight lubricating oils having a viscosity range of from about 40 to about 250 seconds Saybolt at 100 F. or with lubricating oils containing small amounts of certain addition agents such as fats or fatty oils such as tallow, tallow oil, lard oil and the like, oil soluble petroleum sulfonic acid soaps, such as mahogany soaps, and oil soluble naphthenates. Other materials such as the alkali soaps of stearine, lard oil and the like have been used.

Uncompounded lubricating oils of the proper specifications although effective in preventing seizure are undesirable in that they produce discoloration of the rolled sheets and for the further reason that they are difficult to remove by ordinary washing. Other uncompounded lubricating oils do not give the proper lubrication which results in seizure and weaving. The term weaving as used herein and in the appended claims refers to the condition of the rolled metal which prevents it from lying snugly upon a flat surface. In other words, an improperly rolled metal sheet will have an irregular surface which will not permit the sheet to lie snugly upon a flat surface. compounded mineral oils of the type heretofore used cause even more discoloration and staining of the metal during the annealing process than do the uncompounded mineral oils. The compounded oils containing fats and fatty oil such as tallow, lard and the like are further objectionable because of the difficulties encountered in washing the lubricant from the metal.

Heretofore it has been the belief of those in the non-ferrous cold rolling art that the staining of the sheets has been to a great extent due to the presence of acidic materials in the lubricants, and for this reason special efforts have been made to use only such compounded materials which were low in, or free of, acidic properties.

It is, therefore, the primary object of this invention to provide a cold rolling and processing oil, particularly for non-ferrous metals, which does not cause discoloration or staining of the metals, which is easily removed by ordinary washing means, and which produces no weaving effects.

Contrary to the teachings of the prior art I have found that mineral oils compounded with a small amount of naphthenic acid produce superior cold rolling oils for non-ferrous metals. Oils s0 compounded do not cause discoloration or staining of the metals during the annealing process, are easily removed by ordinary washing means, give greater coverage, and completely eliminate "weaving effects. I have found mineral oils having a viscosity range from about 40 seconds to about 250 seconds Saybolt at 100 F. compounded with from about 0.5% to about 30% and preferably from about 1% to about 5% of naphthenic acids produce cold rolling oils possessing all the aforementioned desirable properties. Under certain conditions it is desirable to add small amounts of graphite to the compounded oils.

Exemplary of my invention but not limiting the scope thereof are the followingformulas of various grades of cold rolling and/or processing oils.

Example 1 Naphihvnic acid "per cent" 05-5 Mineral oil "do lo-99.5 Mineral oil characteristics Saybolt viscosity at 100 F. scconds lOO-lOo Gravity degrees A. P. I 20 Flash (minimum) (legrees Fahrenheit 350 Pour test (maximum) do +35 Example 2 Naphthonic acid pcr cent 0.5-5 Mineral oil "do 05-905 Mineral oil characteristics Saybolt viscosity at 100 F. a se(-onds 80-85 Gravity "degrees A. P. I. 29.9 Flash (minimum) degrees Fahrenheit 330 Your test (maximum) do 35 Example 3 053-5 i)509.5 cs Saybolt vi osity at 100 F. seconds 180-185 Gravity degrees A. P. I 27.2 Flash (minimum)degrees Fahrenheit 300 Pour test (maximum) do +40 Example 4 Naphthenic acid p r ccllt 0.5i Mineral oil (lo 9599.5 Mineral oil characteristics Saybolt viscosity at 100 F sccon ls 140-110 Gravity "degrees A. P. I 28 Flash (mininmmLjegrees Fahrenheit 375 Your test (maximum) do r- +40 Example 5 Nanhthenic acid per contw 0.5-5 Mineral oil (lo -9 .5 Graphite do 1-5 For other cold metal working processes such as extrusion, cold drawing and the like it may be desirable to use a larger amount of naphthenic acid, than is used in the cold rolling process. For these other cold metal working processes as much as from about to about 30% of naphthenic acids may be employed.

Although naphthenic acids from any source may be used I prefer to employ naphthenic acids obtained from petroleum oils. The naphthenic acids may be recovered from petroleum oils either by treating the oils with aqueous alkali at elevated temperatures, acidifying the separated or extracted solution of alkali naphthenates, extracting with a low boiling solvent and separating the acid by fractional distillation, or the oil may be distilled in the presence of an alkali and the resulting soap recovered by extraction with alcohol of about 80% strength. Other methods are described in Ellis The Chemistry of Petroleum Derivatives volume II, page 1104 et seq.

It is not intended that the invention be limited to the specific examples given, since obviously many variations may be made without departing from the spirit and scope of the invention.

I claim:

1. A lubricant adapted for the cold working of metals which comprises a mineral oil normally unsuitable for the cold working of metals and a naphthenic acid in an amount sufficient to render said mineral oil suitable for the cold working of said metals.

2. A compounded oil adapted for use in the cold working of metals which comprises a mineral lubricating oil having a Saybolt Universal viscosity at 100 F. of from about 40 seconds to about 250 seconds which oil is normally unsuitable for the cold working of metals and from about 0.5% to about 30% of a naphthenic acid, whereby said mineral lubricating oil is rendered suitable for the cold working of said metal.

3. A method of cold working metals which comprises applying to said metal a thin film of a compound comprising a mineral lubricating oil and from about 0.5% to about 30% of a naphthenic acid.

4. A lubricant adapted for the cold working of non-ferrous metals without staining and weaving which comprises a mineral oil normally ineffective in preventing staining and weaving of the cold worked metal and a naphthenic acid in amounts sufiicient to prevent staining and weaving" of the finished metal.

5. A lubricant as described in claim 4 in which the mineral oil has a Saybolt viscosity of from about 40 to about 250 seconds at F.

6. A compounded oil adapted for use in the cold rolling of copper alloys which is effective in preventing weaving" of the cold rolled copper alloy and staining of said alloy after annealing which comprises a mineral lubricating oil having a Saybolt viscosity at 100 F. of from about 40 seconds to about 250 seconds which oil is normally ineffective in preventing weaving of the cold rolled copper alloy and staining of said alloy after annealing and from about .5% to about 5% of a naphthenic acid.

7. An oil as described in claim 6 in which the naphthenic acids are obtained from a naphthenic base crude oil.

8. A method of cold working non-ferrous metals Without causing discoloration and weaving thereof which comprises applying to said nonferrous metal a thin film of a compound comprising a mineral lubricating oil and from about 0.5% to about 30% of naphthenic acids.

9. The method of cold rolling a copper containing alloy without causing discoloration and weaving which comprises applying to said metal before the same is passed through the cold rolls a thin film of a compound comprising a mineral lubricating oil having a Saybolt viscosity at 100 F. of from about 40 seconds to about 250 seconds and from about 0.5% to about 5% of naplithenic acids obtained from petroleum oils.

10. In the process of cold rolling a copper containing alloy in which the alloy is passed through a series of rolls and subsequently annealed and treated in a pickling bath, the improvement comprising applying to said alloy before the same is passed through the rolls a thin film of a compound comprising a mineral lubricating oil having a Saybolt viscosity at 100 F. of from about 40 seconds to about 250 seconds and which is normally ineffective in preventing weaving" and staining of the rolled alloy and from about .5% to about 5% of a naphthenic acid, whereby weaving and staining of the rolled alloy is substantially avoided.

11. The method of cold rolling a copper containing alloy without causing discoloration and weaving which comprises applying to said metal before the same is passed through the cold rolls a thin film of a compound comprising a mineral lubricating oil having a Saybolt viscosity at 100 F. of from about 40 seconds to about 250 seconds and from about 0.5% to about 5% of naphthenic acids obtained from petroleum oils and a small amount of graphite.

GEORGE W. FLINT. 

